Device for regulating the flow of refrigerants in refrigerating plants



ec. 17, 1935. R. J. CRACKNELL 2,024,721

DEVICE FOR REGULATING THE FLOW OF REFRIGERANTS IN REFRIGERATING PLANTS Filed Jan. 23, 1935 Patented Dec. 17, 1935 UNITED STATES PATENT OFFICE DEVICE FOR REGULATING THE FLOW OF REFBIGERANTS IN REFRIGERATING PLANTS company Application January 23, 1935, Serial No. 3,004 In Great Britain September '7, 1933 5 Claims.

This invention is for improvements in or relating to devices for regulating the flow of refrigerant in refrigerating plant. The invention is particularly concerned with regulating devices of the type which embody float-operated valves interposed between the condenser and the evaporator and which have the float-chamber under the condenser pressure. These regulating devices are intended to pass liquid from the condenser to the evaporator, and it is desirable that as lit tle gas or vapour should be allowed topass as possible.

In regulating devices of this type as heretofore proposed a difficulty is sometimes experienced in getting the liquid to flow from the condenser into the float-chamber. This difliculty is especially liable to occur if the float-chamber is located at a level above the condenser. Another difilculty which is sometimes experienced is that the float-chamber becomes gas-bound. That is to say, the float becomes locked in a position in which it maintains the valve closed. In order to overcome this difficulty a vent pipe or leak passage has been proposed to allow gas or vapour to escape from the upper part of the float-chamber to the evaporator. Owing, however, to the great difference between the pressure in the condenser and that in the evaporator, a relatively large amount of gas or vapour will escape even when the vent pipe has the smallest bore practicable.

It is an object of the present invention to provide a construction of regulating device which shall not be subject to these objections.

According to the present invention in an evaporative refrigerating apparatus there is provided between the condenser and the evaporator an automatic regulating device comprising a float-chamber, a bell-float therein, means for introducing fluid from the condenser beneath the bell-float, a leak in the upper part of the float, a discharge port in the float chamber connected to the evaporator and so disposed as to retain sufficient working fluid therein to seal the bell at all times, a discharge valve for the port and operative connections from the float to the discharge valve such that the valve is closed when the float rises.

It will be appreciated that the leak will enable the gas or vapour pressure inside and above the bell to equalize themselves-thus permitting the bell to fall under its own weight and open the valve. There will therefore be no likelihood of the float becoming gas-bound. Upon the valve opening the gas in the float-chamber will escape to the evaporator until the float-chamber pressure falls sufficiently to admit liquid from the condenser and this liquid will flow through the regulating device until the liquid in the condenser is exhausted, whereupon the flow of gas from the condenser will fill the bell with gas and cause the valve to close by the rising of the bell. Therefore the pressure in the condenser will always be able to cause discharge into the floatchamber.

Preferably, the discharge port is situated in a well separated from the float-chamber by a weir. The weir should be preferably not higher than the top of the float when the valve is closedpreferably slightly below the top of the float in this position.

Preferably, the float encloses a substantially larger horizontal sectional area than the space around it in the float-chamber and it is so positioned that when the valve is closed the float is not entirely submerged. Consequently, when liquid flows into the float from the float-chamber when the valve is closed the level in the floatchamber falls rapidly for even a small flow of liquid into the float and the opening of the valve occurs more promptly. In other words, the device is more sensitive and less gas needs to flow from the condenser for the purpose of operating the float.

The following is a description by way of example of one construction in accordance with the invention with reference to the accompanying drawing, in which- Figure 1 is a vertical section of a regulating device in accordance with the invention, and

Figure 2 is a plan of the same with the cover removed.

In the drawing, H is a casing of a float-chamber I2, which casing is designed to withstand an internal pressure equal to that of the condenser of the refrigerating apparatus in which the regulating device is to be employed. The casing H is provided with a removable cover 13 held by set screws 14 and it has an inlet l5 and an outlet IS, the inlet l5 being intended to be connected to the outlet for condensed liquid of the condenser, while the outlet I6 is to be connected to the evaporator.

The outlet I6 is located at the bottom of a well ll on the side of the casing H and between the well !1 and the outlet passage 16 there is an outlet port 58 in a valve seating [9. The well I! is separated from the float chamber l2 by a weir 29. On the edge of the weir there is supported a bearing 21 for the pivot 22 of a floatlever 23. The float-lever is pivoted at 24 to the stem of a conical valve 25 which works on the seating I9 and serves, when closed, to seal the outlet port I 8. At the other end of the float-lever 23' there is hung by a pivot pin 26 a bell-float 21. The bell-float is made of a diameter very little smaller than the dimensions of the inside of the casing l l of the float-chamber and it is 'open at the bottom end so that its open under side overlies the end of a pipe 28 screwed into the inlet I5. In its upper Wall the bell-float 21 is provided with a small leak aperture 29. The weight of the float must be so proportioned that r when the interior of the bell is filled with liquid,

it will be heavy enough to sink and pull the valve offits seat against the condenser pressure, and it must at thesaine time be light enough to float when a sufficient quantity of liquid from the interior is displaced by gas.

In the operation of this regulator, assuming the parts to be in the position shown in the drawing with the bell-float 2! sunk to its lowermostrposition and the valve 25 open, liquid is forced from V the condenser through the inlet l 5 into the floatchamber l2 and the entry of this liquid causes an overflow over the weir 20 into the well l1 and out through the valve and port l8 to the evaporator. As soon as the liquid available in the condenser has all flowed into the float-chamber a small amount of gas comes through the inlet l5 and entering below the bell 2'! it displaces the liquid therein, causing the displaced liquid also to overflow the weir and pass to the evaporator. As soon as the amount of gas in the bell is sufficient to give it buoyancy the bell is caused to rise and to close the valve 25. Gas continues to flow into the float-chamber for a short time until the pressure in the regulating device rises to the pressure in the condenser. Flow then ceases and liquid accumulates in the condenser while the gas beneath the bell gradually leaks out through the leak hole 253., As a result the buoyancy of the bell decreases and the bell begins to sink. The leaking of the gas out of the bell-float allows some of the liquid in the float-chamber I 2 to pass back into the bell-float and as the cross-sectional area enclosed by the bell is much greater than the surrounding horizontal area in the float-chamber, the corresponding fall of liquid level in the floatchamber will be rapid. A small. transfer of gas from beneath the bell to the space above it will therefore suffice to cause the bell to sink again, partly by the loss of buoyancy and partly by the fall of liquid level in the float chamber. The valve 25 will therefore very soon open again, whereupon any small quantity of liquid in the well I! is first discharged to the evaporator, followed by a small quantity of gas from the upper part of the float-chamber, so that'the pressure, which had been equal to the condenser pressure, now falls sufliciently to permit the entry of further condensed liquid from the condenser.

The cycle of operations is then repeated. Owing to the arrangements for the prompt opening of the valve with a slight leakage through the leak hole 29 the apparatus is highly sensitive and works with only a very small amount of gas passing to the evaporator, much smaller than the amount of gas which would pass by a direct leak from the space in the float-chamber to the evaporator in the known apparatus as hereinbefore referred to.

1. In an evaporative refrigerating apparatus, the provision between the condenserand the evaporator of an automatic regulating device comprising a float chamber, a bell-float therein, means for introducing fluid from the condenser beneath the bell-float, a well adjacent the float chamber and connected thereto, a discharge port in the well connected to the evaporator, the well being so disposed as to retain sufficient working fluid in the float chamber to seal the open end of the bell-float at all times, a discharge valve for the port, and operative connections from the bellfloat to the discharge valve such that the valve is 25 closed when the bell-float rises.

2. In an evaporative refrigerating. apparatus an automatic regulating device as claimed in claim 1 wherein the said well is separated from the float-chamber by a weir and said discharge port is below the weir.

3. In an evaporative refrigerating apparatus an automatic device as claimed in claim 1 wherein the float is so positioned in the float-chamber that when the valve closes the level of the liquid in the float-chamber is not above the upper wall of the float substantially as and for the purpose described.

4. In an evaporative refrigerating apparatus an automatic device as claimed in claim 1 where in the float is so positioned in the float-chamber that when the valve closes the level of the liquid in the float-chamber is not above the upper wall of the float and wherein the float encloses a substantially larger horizontal sectional area than the space around it in the float-chamber, for the purpose described.

5. An automatic regulating device for an evaporative refrigerating apparatus comprising in combination a float-chamber having a discharge port located at a level above the bottom of the chamber, a discharge valve for the discharge port, a bell-float in the chamber operatively connected to the discharge valve whereby thevalve is direct- 

